This heatmap visualizes a matrix of data values using a color gradient that transitions from dark blue through purple and red to yellow, encoding increasing magnitude. Each cell is rendered as a small rectangle in an SVG grid, with 80 columns and 37 rows, spanning a 900 by 500 pixel plotting area. The color scale is defined as a linear gradient with 18 stops, mapping low values to deep navy and high values to pale yellow. The visualization is generated from a gist by aaizemberg and uses SVG for rendering, with no axes or labels shown.